1. Field of the Invention
This invention relates to a method of manufacturing insulated gate type field effect semiconductor devices by selective oxidation process.
2. Description of the Prior Art
To cope with the recent trend that the integration degree of a large scale integrated circuit device increases more and more, effect has been made to reduce pattern size of such device and prevent breaking of metal layer wiring thereof. To this end, it has been proposed to manufacture such a type of semiconductor device by so-called selective oxidation process wherein oxide film is selectively formed only on desired portions of the substrate surface and part of such oxide film is buried in the substrate. In such a conventional method, however, there is the tendency that defect, such as scar, crack, distortion, dislocation or the like is caused to occur in the substrate surface during elimination of silicon nitride film which is formed in the course of the manufacturing process; due to such defect, the break-down voltage of the resulting device is decreased.